A Radiosorbent Technique for the Assay of Serum Vitamin B₁₂

Abstract

A radiosorbent technique for serum B₁₂ was developed, using intrinsic factor coupled to polysaccharide particles. 111 healthy subjects, aged 17–76 years, had a mean serum B₁₂ level of 530 pg/ml, with 95 % confidence limits of 288 and 980 pg/ml. Sera from 1,250 patients were assayed with the present method and Euglena gracilis. The results correlated closely, although numerically different. The same degree of discrimination was obtained between B₁₂ deficient and non B₁₂ deficient samples. The radiosorbent assay was easier and more rapid with a higher reproducibility.

Key Words:

• B₁₂ radio assay
• B₁₂ deficiency
• Euglena B₁₂ assay
• isotopic B₁₂ assay
• radiosorbent assay
• serum B₁₂ level